Re: [PATCH 1/2] iphlpapi: Use a standalone buffer in IcmpSendEcho().

[Zhiyi Zhang]

On Thu 6 21 17:35, Huw Davies wrote:
> On Fri, Jun 15, 2018 at 12:23:23PM +0800, Zhiyi Zhang wrote:
> > Fix https://bugs.winehq.org/show_bug.cgi?id=43252
> >
> > The old implementation uses user provided buffer to receive
> > packet data, which is alway not enough, causing data corruptions
> > or incorrectly timeout.
> > Signed-off-by: Zhiyi Zhang
> >
> > dlls/iphlpapi/icmp.c           | 38 +++++++++++++++++++++++++++-------
> >  dlls/iphlpapi/tests/iphlpapi.c | 21 +++++++++++++++----
> >  2 files changed, 47 insertions(+), 12 deletions(-)
> >
> > diff --git a/dlls/iphlpapi/icmp.c b/dlls/iphlpapi/icmp.c
> > index ebc2f2b65c..7c91443598 100644
> > --- a/dlls/iphlpapi/icmp.c
> > +++ b/dlls/iphlpapi/icmp.c
> > @@ -113,6 +113,9 @@ typedef struct {
> >  #define IP_OPTS_DEFAULT     1
> >  #define IP_OPTS_CUSTOM      2
> >
> > +#define MAXIPLEN            60
> > +#define MAXICMPLEN          76
>
> Out of interest, how did you get to 76?

That was copied from https://github.com/iputils/iputils/blob/master/ping.c#L76
> > -
> >
> > /* The sequence number is unique process wide, so that all threads
> > - have a distinct sequence number.
> >
> > */
> > @@ -270,13 +273,14 @@ DWORD WINAPI IcmpSendEcho(
> >      icmp_t* icp=(icmp_t*)IcmpHandle;
> >      unsigned char* reqbuf;
> >      int reqsize;
> > -
> >
> > unsigned char* repbuf;
> > -
> >
> > int repsize;
> >
> > struct icmp_echo_reply* ier;
> > struct ip* ip_header;
> > struct icmp* icmp_header;
> > char* endbuf;
> > int ip_header_len;
> > - int maxlen;
> > struct pollfd fdr;
> > DWORD send_time,recv_time;
> > struct sockaddr_in addr;
> >
> > @@ -312,6 +316,16 @@ DWORD WINAPI IcmpSendEcho(
> >          return 0;
> >      }
> > - /* max ip header + max icmp header and error data + reply size(max 65535 on Windows) */
> > - /* FIXME: request size of 65535 is not supported yet because max buffer size of raw socket on linux is 32767 */
> > - repsize=MAXIPLEN+MAXICMPLEN+(ReplySize&0xFFFF);
> > - repbuf=HeapAlloc(GetProcessHeap(), 0, repsize);
> > - if (reqbuf==NULL) {
>
> This should be repbuf.
> > -
> >    HeapFree(GetProcessHeap(), 0, reqbuf);
> > -
> >    SetLastError(ERROR_OUTOFMEMORY);
> > -
> >    return 0;
> > - }
> > - icmp_header=(struct icmp*)reqbuf;
> >    icmp_header->icmp_type=ICMP_ECHO;
> >    icmp_header->icmp_code=0;
> >
> > @@ -367,9 +381,7 @@ DWORD WINAPI IcmpSendEcho(
> >      fdr.events = POLLIN;
> >      addrlen=sizeof(addr);
> >      ier=ReplyBuffer;
> > -
> >
> > ip_header=(struct ip *) ((char *) ReplyBuffer+sizeof(ICMP_ECHO_REPLY));
> > endbuf=(char *) ReplyBuffer+ReplySize;
> > -
> >
> > maxlen=ReplySize-sizeof(ICMP_ECHO_REPLY);
> >
> > /* Send the packet */
> > TRACE("Sending %d bytes (RequestSize=%d) to %s\n", reqsize, RequestSize, inet_ntoa(addr.sin_addr));
> >
> > @@ -407,10 +419,11 @@ DWORD WINAPI IcmpSendEcho(
> >      }
> >  /* Get the reply */
> > - ip_header=(struct ip*)repbuf;
> > ip_header_len=0; /* because gcc was complaining */
> > while (poll(&fdr,1,Timeout)>0) {
> >     recv_time = GetTickCount();
> > -
> >    res=recvfrom(icp->sid, (char*)ip_header, maxlen, 0, (struct sockaddr*)&addr,&addrlen);
> > -
> >    res=recvfrom(icp->sid, (char*)repbuf, repsize, 0, (struct sockaddr*)&addr, &addrlen);
> >    TRACE("received %d bytes from %s\n",res, inet_ntoa(addr.sin_addr));
> >    ier->Status=IP_REQ_TIMED_OUT;
> >
> > @@ -508,6 +521,12 @@ DWORD WINAPI IcmpSendEcho(
> >              else             Timeout = 0;
> >              continue;
> >          } else {
> > -
> >        /* Check free space, should be large enough for an ICMP_ECHO_REPLY and remainning icmp data */
> > -
> >        if (endbuf-(char *)ier < sizeof(struct icmp_echo_reply)+(res-ip_header_len-ICMP_MINLEN)) {
> > -
> >            res=ier-(ICMP_ECHO_REPLY *)ReplyBuffer;
> > -
> >            SetLastError(IP_GENERAL_FAILURE);
> > -
> >            goto done;
> > -
> >        }
> >        /* This is a reply to our packet */
> >        memcpy(&ier->Address,&ip_header->ip_src,sizeof(IPAddr));
> >        /* Status is already set */
> >
> > @@ -515,7 +534,7 @@ DWORD WINAPI IcmpSendEcho(
> >              ier->DataSize=res-ip_header_len-ICMP_MINLEN;
> >              ier->Reserved=0;
> >              ier->Data=endbuf-ier->DataSize;
> > -
> >        memmove(ier->Data,((char*)ip_header)+ip_header_len+ICMP_MINLEN,ier->DataSize);
> > -
> >        memcpy(ier->Data, ((char *)ip_header)+ip_header_len+ICMP_MINLEN, ier->DataSize);
> >        ier->Options.Ttl=ip_header->ip_ttl;
> >        ier->Options.Tos=ip_header->ip_tos;
> >        ier->Options.Flags=ip_header->ip_off >> 13;
> >
> > @@ -523,7 +542,7 @@ DWORD WINAPI IcmpSendEcho(
> >              if (ier->Options.OptionsSize!=0) {
> >                  ier->Options.OptionsData=(unsigned char *) ier->Data-ier->Options.OptionsSize;
> >                  /* FIXME: We are supposed to rearrange the option's 'source route' data */
> > -
> >            memmove(ier->Options.OptionsData,((char*)ip_header)+ip_header_len,ier->Options.OptionsSize);
> > -
> >            memcpy(ier->Options.OptionsData, ((char *)ip_header)+ip_header_len, ier->Options.OptionsSize);
> >            endbuf=(char*)ier->Options.OptionsData;
> >        } else {
> >            ier->Options.OptionsData=NULL;
> >
> > @@ -531,9 +550,8 @@ DWORD WINAPI IcmpSendEcho(
> >              }
> >          /* Prepare for the next packet */
> > -
> >        endbuf-=ier->DataSize;
> >        ier++;
> > -
> >        ip_header=(struct ip*)(((char*)ip_header)+sizeof(ICMP_ECHO_REPLY));
> > -
> >        maxlen=endbuf-(char*)ip_header;
> >
> >        /* Check out whether there is more but don't wait this time */
> >        Timeout=0;
> >
> > @@ -542,6 +560,10 @@ DWORD WINAPI IcmpSendEcho(
> >      res=ier-(ICMP_ECHO_REPLY*)ReplyBuffer;
> >      if (res==0)
> >          SetLastError(IP_REQ_TIMED_OUT);
> > - else
> > -
> >    SetLastError(NO_ERROR);
>
> This hunk looks like a separate change so should be a separate patch.
> Note, in general setting last error to NO_ERROR looks wrong, though it may
> be needed in this case.
>
> Huw.